I would never ever block a fuel nozzle open for any reason, I've seen truckers do it at truck stops and dump a lot of fuel on the ground because the nozzle did not turn off. I would say if you coaches fuel fill tube will not handle truck stop fueling don't fuel there. On my Thunder I go straight into the tank so I do not have this problem, used to have a service truck that was a bear to get fuel in one of the tanks and it was the fill tube. Just had to live with it.